1. Field of the Invention
This invention relates to improvements in peelable seals, particularly peelable seals such as those utilized in ultrasonically-sealable packaging materials and packages.
2. Prior Art
Peelable seals are known in the prior art for numerous advantages. Particularly such seals provide a means for opening a package by pulling on two layers of the package so that the package opens relatively easily and yet is of such strength that the package survives in the chain of distribution. The peelable seal allows a consumer to open the package, yet imparts sufficient strength to the package to be handled from manufacturer to user. Peelable seals allow a package to be made with a predetermined seal strength. The seal strength requirements usually vary according to the size of the package and the items contained in the package.
Film-type packaging material is commonly used for packaging snacks such as potato chips, corn chips, popcorn, and the like, as well as other numerous items. Such packaging is conventionally heat-sealed. Heat sealing, however, typically requires expensive packaging materials. Ultrasonic sealing is not readily commercially available, but is known in the art and can utilize less expensive packaging materials.
There is a need in the art for a peelable seal of less expensive packaging material which is ultrasonically sealable, but not readily heat-sealable.